Buggy code:
public class ButtonPage extends WicketExamplePage { public ButtonPage ( ) { } protected void explain ( ) { <START_BUG> String html = "<seq2seq4repair_space><form<seq2seq4repair_space>wicket:id=\"form\">\n" + ( ( ( "<seq2seq4repair_space><input<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"non<seq2seq4repair_space>wicket<seq2seq4repair_space>submit<seq2seq4repair_space>button\"<seq2seq4repair_space>//>\n" + "<seq2seq4repair_space><input<seq2seq4repair_space>wicket:id=\"button1\"<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"default<seq2seq4repair_space>wicket<seq2seq4repair_space>button\"<seq2seq4repair_space>//>\n" ) + "<seq2seq4repair_space><input<seq2seq4repair_space>wicket:id=\"button2\"<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"wicket<seq2seq4repair_space>button<seq2seq4repair_space>with<seq2seq4repair_space>immediate<seq2seq4repair_space>==<seq2seq4repair_space>true\"<seq2seq4repair_space>//>\n" ) + "<seq2seq4repair_space><//form>" ) ; <END_BUG> String code = "&nbsp;&nbsp;&nbsp;&nbsp;////<seq2seq4repair_space>Add<seq2seq4repair_space>a<seq2seq4repair_space>form<seq2seq4repair_space>with<seq2seq4repair_space>an<seq2seq4repair_space>onSubmit<seq2seq4repair_space>implementation<seq2seq4repair_space>that<seq2seq4repair_space>sets<seq2seq4repair_space>a<seq2seq4repair_space>message\n" + ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( "&nbsp;&nbsp;&nbsp;&nbsp;Form<seq2seq4repair_space>form<seq2seq4repair_space>=<seq2seq4repair_space>new<seq2seq4repair_space>Form(\"form\")<seq2seq4repair_space>{\n" + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;protected<seq2seq4repair_space>void<seq2seq4repair_space>onSubmit()<seq2seq4repair_space>{\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;info(\"Form.onSubmit<seq2seq4repair_space>executed\");\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;};\n" ) + "\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;Button<seq2seq4repair_space>button1<seq2seq4repair_space>=<seq2seq4repair_space>new<seq2seq4repair_space>Button(\"button1\")<seq2seq4repair_space>{\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;protected<seq2seq4repair_space>void<seq2seq4repair_space>onSubmit()<seq2seq4repair_space>{\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;info(\"button1.onSubmit<seq2seq4repair_space>executed\");\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;};\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;form.add(button1);\n" ) + "\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;Button<seq2seq4repair_space>button2<seq2seq4repair_space>=<seq2seq4repair_space>new<seq2seq4repair_space>Button(\"button2\")<seq2seq4repair_space>{\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;protected<seq2seq4repair_space>void<seq2seq4repair_space>onSubmit()<seq2seq4repair_space>{\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;info(\"button2.onSubmit<seq2seq4repair_space>executed\");\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;};\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;button2.setDefaultFormProcessing(false);\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;form.add(button2);\n" ) + "\n" ) + "&nbsp;&nbsp;&nbsp;&nbsp;add(form);" ) ; add ( new ExplainPanel ( html , code ) ) ; } }

Fix:
String html = "<seq2seq4repair_space><form<seq2seq4repair_space>wicket:id=\"form\">\n" + ( ( ( "<seq2seq4repair_space><input<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"non<seq2seq4repair_space>wicket<seq2seq4repair_space>submit<seq2seq4repair_space>button\"<seq2seq4repair_space>//>\n" + "<seq2seq4repair_space><input<seq2seq4repair_space>wicket:id=\"button1\"<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"default<seq2seq4repair_space>wicket<seq2seq4repair_space>button\"<seq2seq4repair_space>//>\n" ) + "<seq2seq4repair_space><input<seq2seq4repair_space>wicket:id=\"button2\"<seq2seq4repair_space>type=\"submit\"<seq2seq4repair_space>value=\"wicket<seq2seq4repair_space>button<seq2seq4repair_space>with<seq2seq4repair_space>setDefaultFormProcessing(false)\"<seq2seq4repair_space>//>\n" ) + "<seq2seq4repair_space><//form>" ) ;